a. The field of art to which the invention pertains comprises the art of liquid dispensing and leak testing therefor.
B. It is recognized that even minimal pipe leakage of a fluid commodity being transmitted in underground distribution piping represents an accumulative economic loss that is preferably to be avoided. At the same time, where the leaking fluid is characterized as being toxic, combustible or having other properties requiring controlled containment, its free uncontrolled existence in the escaping environment can pose serious hazards to health and/or safety.
Typically confronted with such problems of underground leakage is the gasoline service station at which petroleum products, principally gasoline, are pumped significant distances from an underground storage tank to the aboveground dispenser from which a customer acquires his automobile fuel needs. Should a leak occur in the delivery piping, it can frequently go undetected until long after its accumulated ground saturation reaches hazardous proportions. For that reason, in conjunction with the current trend toward higher fuel costs, along with current emphasis on increased energy conservation, the need to ascertain existence of leaks in the piping network on a regular basis has become even more of a necessity than ever before. It is important, therefore, that leak detection equipment for that purpose not only be available but that it be available at a nonprohibitive cost and with ease of operation for the service station proprietor. One such system and method is disclosed in U.S. Pat. No. 3,940,020.